34 ///// — r<il('oiifolo[/i/ of the Trinity Division. 



Dr. Roomer de.scril)ed this large and abundant species of the 

 Glen Rose beds from specimens collected on the Pedernalis 

 river. He also descri1)ed Natica [Ti/lustoiii(i) irra^grandis, which 

 he asserted differed onl}^ by its larger size. 



The species occurs in the greatest abundance throughout the 

 extent of the Glen Rose beds in Arkansas, Texas, and Mexico, 

 and is preserved only as casts, without shell structure. From 

 observations of hundreds of individuals, I am of the opinion that 

 the two species of Roemer are identical. 



These forms are indistinguishable from man}' species described 

 from the Neocomian of France and Spain, where the genus Ttj- 

 lo.^fomn has its culnunation, ranging, according to Zittel, from the 

 U2:)pcr Jurassic. Tyiostoma similiimnn Choffat, from Portugal, a 

 characteristic Neocomian form, is quite closely related, if not 

 identical with the Texas species. It also resembles N. f/i!/((s 

 Bonn, of the Jurassac. 



The specimen iigured here is. a large flattened individual, 

 illustrated in order to show the size and variation in comparison 

 with the t3^pical forms figured by Roemer. 



This form occurs throughout the Neocomian of Mexico, in 

 Venezuela, Bogota, and on the central Pacific coast of Souili 

 America, and. is one of the distinguisliing fossils of tlie Glen Rose 

 beds. 



Vicarya bianneri sp. nov. 



Plate V, Figs. 1-7. 



Pleurocera dromhifornlis (Schlotheim) Hill. Neozoic Geology 

 of Southwest Arkansas, p. 129, plate ii. figs. 1,2, 3, 4, 5, G, 7, 

 7a, 7b, 8, 9, 10, 11, 12, 12a; i)late iii,' figs.G, Ga, Gh, Gf, copies of 

 European figures. 



Compare — 



Vicarya helvetica Verneuil and De Loriere. Description des 

 Fossiles du Neocomien Supcrieur de Utrillas et ses Environs, p. 

 2, plate i, fig. 1. 



Vicarya. lujani Verneuil and De Loriere. Ibid., ]>. 5, plate i, 

 fig. 3. 



Vicarya stromhiformis Verneuil and Do fioriere. Il)id., \). 7, 

 ])late i, fig. 4. 



Vicarya pradoi Verneuil ;ind De Ivoriere. Ibid., p. 1<>, [)late i, 

 fiff. 5. 



